Inheritance Plugin Question

I try to let two generated classes implement their own interface.
Example
Class A should implement IA
Class B should implement IB

This is working so far (wiht XInheritance plugin) as long as class A and B are implementing their interfaces.
But the interfaces are not used:
e.g. the object factory returns on createA and createB methods A / B classes instead of IA and IB.
Even worse:
If class A holds a List of type B then the created get method is
public List getBs instead of public List getBs.

For me and my current situation: I can work around this because B is not necessarily forced to implement IB.
But it would be nicer to work on interfaces everywhere possilbe so I wanted to ask and clarify.
If this is not possible at the moment then just tell me and close the issue.